Write your own atoi

Implement atoi to convert a string to an integer.

Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input cases.

Notes: It is intended for this problem to be specified vaguely (ie, no given input specs). You are responsible to gather all the input requirements up front.

int myAtoi(string str) {
    int sign = 1, base = 0, i = 0;

    // 1. Discard empty space
    while (str[i] == ' ') i++;

    // 2. Optional initial plus or minus sign 
    if (str[i] == '-') {
        sign = -1, i++;
    } else if (str[i] == '+') {
        sign = 1, i++;
    }

    // 3. Convert digit char to integer
    while (isdigit(str[i])) {
        int temp = 10*base + str[i++] - '0';
        // 4. Check for overflow
        if (temp/10 != base) {
            return sign == 1 ? INT_MAX : INT_MIN;
        }
        base  = temp;
    }
    return base * sign;
}